Cost-minimization analysis of GSTP1c.313A>G genotyping for the prevention of cisplatin-induced nausea and vomiting: A Bayesian inference approach.

BACKGROUND: Chemotherapy-induced nausea and vomiting are concerning adverse events resulting from cancer treatment, and current guidelines recommend the use of neurokinin-1-selective antagonists, such as fosaprepitant, in highly emetogenic schemes. However, the implementation of this strategy may be limited by the cost of treatment. GSTP1 c.313A>G genotype was recently described as a predictor of vomiting related to high-dose cisplatin. We hypothesized that the inclusion of routine GSTP1 c.313A>G screening may be promising in financial terms, in contrast to the wide-spread use of fosaprepitant. METHODS: A cost-minimization analysis was planned to compare GSTP1 c.313A>G genotyping versus overall fosaprepitant implementation for patients with head and neck cancer under chemoradiation therapy with high-dose cisplatin. A decision analytic tree was designed, and conditional probabilities were calculated under Markov chain Monte Carlo simulations using the Metropolis-Hastings algorithm. The observed data included patients under treatment without fosaprepitant, while priors were derived from published studies. RESULTS: To introduce screening with real-time polymerase chain reaction, an initial investment of U$ 39,379.97 would be required, with an amortization cost of U$ 7,272.97 per year. The mean cost of standard therapy with fosaprepitant is U$ 243.24 per patient, and although the initial cost of routine genotyping is higher, there is a tendency of progressive minimization at a threshold of 155 patients (Credible interval-CI: 119 to 216), provided more than one sample is incorporated for simultaneous analysis. A resulting reduction of 35.83% (CI: 30.31 to 41.74%) in fosaprepitant expenditures is then expected with the implementation of GSTP1 c.313A>G genotyping. CONCLUSION: GSTP1 c.313A>G genotyping may reduce the use of preventive support for chemotherapy induced nausea and lower the overall cost of treatment. Despite the results of this simulation, randomized, interventional studies are required to control for known and unknown confounders as well as unexpected expenses.

Cost-utility analysis of aprepitant for patients who truly need it in Japan.

PURPOSE: Neurokinin-1 receptor antagonist (NK1RA) is recommended to prevent chemotherapy-induced nausea and vomiting (CINV) in patients who receive highly or moderately emetogenic chemotherapy (HEC or MEC, respectively). We previously reported that aprepitant, an NK1RA, was needed to control CINV in 43% and 12% of patients who received HEC and MEC, respectively (Support Care Cancer 23:905-912, 2015). To elucidate the cost-effectiveness of aprepitant in these patients, a cost-utility analysis according to the necessity of aprepitant was performed. METHODS: A decision-analytic model was developed according to the necessity of aprepitant and CINV responses in both acute and delayed phases of chemotherapy. Probabilities of health states and medical costs were derived from the results of the abovementioned trial. RESULT: In patients who received HEC and needed aprepitant, the incremental cost-effectiveness ratio (ICER) with aprepitant, relative to the regimen with no aprepitant, was 7912 US dollars (USD) per quality-adjusted life year (QALY) gained, which was far below the commonly accepted threshold of 50,000 USD/QALY. The ICER was 27,457 USD/QALY in patients who received MEC and needed aprepitant. In contrast, in patients who received HEC or MEC but did not need aprepitant, the ICER was 175,959 or 478,844 USD/QALY, respectively. CONCLUSION: Regardless of whether a patient received HEC or MEC, aprepitant use was highly cost-effective for patients who truly needed it. These results warrant further research to predict the necessity of NK1RA treatment before initiating emetogenic chemotherapies.